Slurry catalyst compositions and means for their preparation and use are known in the refining arts. Some examples are discussed below.
U.S. Pat. No. 4,710,486 discloses a process for the preparation of a dispersed Group VI B metal sulfide hydrocarbon oil hydroprocessing catalyst. Process steps include reacting aqueous ammonia and a Group VI B metal compound, such as molybdenum oxide or tungsten oxide, to form a water soluble oxygen-containing compound such as ammonium molybdate or tungstate.
U.S. Pat. No. 4,970,190 discloses a process for the preparation of a dispersed Group VI B metal sulfide catalyst for use in hydrocarbon oil hydroprocessing. This catalyst is promoted with a Group VIII metal. Process steps include dissolving a Group VI B metal compound, such as molybdenum oxide or tungsten oxide, with ammonia to form a water soluble compound such as aqueous ammonium molybdate or ammonium tungstate.
U.S. Pat. Nos. 5,164,075 and 5,484,755, which are incorporated by reference, disclose processes for preparation of high activity slurry catalysts for hydroprocessing heavy hydrocarbon oils produced from Group VI B metal compounds. An aqueous mixture of the metal compound is sulfided with from greater than about 8 to about 14 standard cubic feet of hydrogen sulfide per pound of Group VI B metal. These patents demonstrate a process of forming a slurry catalyst precursor and adding it to a heavy feed oil to form the active catalyst.
U.S. Pat. Nos. 5,164,075 and 5,484,755 do not demonstrate the criticality of the oil viscosity in the formation of a highly active catalyst composition, nor the significance of using two distinctly different oils in forming such catalyst composition. In the inventions disclosed in these patents, the failure to form the oil and water emulsion or the slurry phase results in an inactive catalyst or a catalyst having low activity.
U.S. Pat. Nos. 5,162,282 and 5,178,749 are directed to processes for hydroprocessing of heavy hydrocarbonaceous oils. In U.S. Pat. No. 5,162,282, a catalyst precursor is prepared by reacting a Group VI B metal compound with a sulfiding agent in an aqueous environment substantially in the absence of oil. The precursor is heated to convert it to an active catalyst, which subsequently contacts feed at hydroprocessing conditions. In U.S. Pat. No. 5,178,749, an active catalyst slurry is prepared by sulfiding an aqueous mixture of a Group VI B metal compound with hydrogen sulfide gas. The slurry is introduced, along with the oil to be treated, into a fixed or ebullating bed of hydrodesulfurization-hydrodemetalation catalyst at hydroprocessing conditions. Although both of these patents disclose hydroprocessing with catalyst formed from precursors or slurries comprising Group VI B metal compounds, neither involves the use of two distinctly different oils in the formation of the catalyst.
This application discloses a new slurry catalyst composition that is highly active. This activity results from preparation of the catalyst using a process employing two hydrocarbon oils having appropriate viscosity ranges at 212° F.
The first heavier oil is preferably a vacuum gas oil (VGO) and the second is preferably a light naphtha.